This invention relates to a tunable optical device and a method for the manufacture thereof.
There have heretofore been proposed to the art various forms of thin-film dye lasers. For example, those of one construction are known to be formed by disposing rhodamine 6G in gelatin films and exposing the films in periodic patterns to light (Applied Physics Letters, Vol. 8 No. 4, 1972, pp 152-154) and those of another construction are produced by forming gratings of periodic patterns on a fused silica by the ion-milling technique and coating the formed grating with a polyurethane film doped in advance with rhodamine 6G. Both types are known to generate laser beams upon irradiation of the grating with an ultraviolet ray (Applied Physics Letters, Vol. 21 No. 10, 1972, pp 494-496).
These dye lasers of the prior art, however, invariably have a disadvantage that the wavelengths of the generated beams cannot be varied without varying the periods of their gratings or varying the refractive indexes of the thin films used to coat their grating regions.
An object of the present invention is to provide a tunable optical device capable of operating with varying wavelengths of light.